In such an X-ray imaging apparatus, when adjusting an X-ray radiation field which is a range of an X-ray irradiated from an X-ray tube to a subject using a collimator, the irradiation field of the X-ray to be adjusted by the collimator mechanism is confirmed by forming an irradiation field of visible light by turning on the collimator lamp arranged on a side opposite to the subject with respect to the collimator and visually recognizing the irradiation field of the visible light.
In such an X-ray imaging apparatus, it is preferable that the brightness of the light irradiation field by the collimator lamp be as bright as possible for positioning the imaging. However, particularly when imaging a head portion or a neck portion, the light irradiation field is positioned near the face of the subject, so when the operator turns on the collimator lamp, there is a disadvantage that the light directly enters the subject's eye, making the subject feel uncomfortable. Under the circumstance, Patent Document 1 discloses an X-ray imaging apparatus. In the imaging apparatus, when the lamp lighting switch is turned to light the collimator lamp, time measurement is started by a timer and it is judged whether or not head-and-neck imaging is performed based on portion information input from the outside. Only in the case of performing head-and-neck imaging, the lamp voltage setting signal to be output to the lamp power supply circuit is controlled so that the voltage applied to the collimator lamp gradually increases and reaches a predetermined value.